I know this all too well.
I have made it out of that "get mad at a pen dropping" stage, yet after I got the world dumped on my shoulders I'm right back at it. Just in a lesser form. I don't get as mad, but I get annoyed really easily. And when I do get mad, it's like they just dropped Czar Bomba.
Take some time out of the day,and go walking on some trails out in the woods. Or go to a park alone. Don't bring any music, or a phone, just you. Think about the things you do. Why do you get mad? You'll be surprised to see that in the end, you just think about things thst used to make you mad to fuel the new anger. Just to be angry for a few more minutes or hours. I can tell you know, it's all about the feeling. Once you realize that it is negative to both yourself and your peers, you should be able to tone it down and focus on the nicer things in life.
I swear the grass was just that much greener after walking the trails for a few hours a day. I had a lot of revalations at that time. I found out what I wanted to do with my life, I stopped my anger, and I organized my life up. Life was 1,000x easier.
It also helps to like Iron Man
I recently went back into the anger due to my lack of ability due to my heart. I should make an arc reactor,